1. Field of the Invention
The present invention relates to an image forming apparatus and, more particularly, to a portable image forming apparatus constituted by a combination of e.g., an image sensor and a thermal printer.
2. Description of the Related Art
A scanner printer is used as a type of image forming apparatus. In this printer, a document is scanned by an image sensor to generate an electrical signal corresponding to a document image, and printing is performed by driving a head of a thermal printer in accordance with this electrical signal. The outer shape of such a printer is generally rectangular. In this printer, a color contact sensor (line sensor) is used as an image sensor. The color contact sensor is constituted by a CCD including R (red), G (green), and B (blue) filters or complementary color filters. Generally, this image sensor performs scanning once, and stores data obtained by this operation in a memory so as to generate desired image data. A thermal head of the thermal printer is arranged on the operator side so as to oppose a platen roller. Although paper serving as an image receiving member is reciprocated during color image printing, printing is performed only in one moving direction of the paper. Therefore, when printing of one cycle is completed, the paper is returned to a printing position, and printing is resumed from this position.
Such an image forming apparatus has the following drawbacks. For example, if the thermal head is arranged on the operator side of the platen roller, paper must be set by inserting it from the rear side of the platen roller, and must be removed from the operator side of the platen roller, thereby posing a problem that setting of paper is cumbersome. Moreover, since paper is returned to a printing position upon printing in only one direction so as to perform next printing, paper must be moved many times. Therefore, a time required to form a color image on a sheet of paper is inevitably increased. Accompanied with this problem, color misregistration tends to occur.
In order to eliminate the above-described drawbacks, a demand has been arisen for a portable image forming apparatus which can be manufactured at low cost.